I am using MaxQData to capture the data via GPS.
I am recording the video via Aiptek HD.
At home I use Movie Maker in Windows 7 to convert to wmv.
I use MaxQData on the desktop to pair the data and video and create the overlay.
I then use Movie Maker to add a title.
You can build the system by ordering the software from MaxQData, sourcing a GPs buletooth puck, and a Windows Mobile PDA.
Should be right about $300 for all if you find the PDA used.
http://www.maxqdata.com/DIY.htm